Resolution criteria

The average age of senators in the 119th Congress is 64 years old, as of January 2025. This market resolves based on the average age of all 100 U.S. senators on January 3, 2029 (the first day of the 121st Congress). Resolution will be determined by calculating the mean age of all seated senators on that date using publicly available biographical data from the Congressional Research Service or the Biographical Directory of the United States Congress.

Background

The Senate has reversed its aging trend following the death or retirement of some of its oldest members, with the new Senate's median age at 64.7 years, down from 65.3 at the start of the previous Congress. Baby Boomers still comprise a solid majority of the Senate at 60 out of 99 senators, while Generation X is the largest generation in the House with 180 members. Many older Democrats are opting to pass the torch to a younger generation, including Sens. Dick Durbin and Jeanne Shaheen.

Considerations

The 2026 midterm elections will significantly impact Senate composition. Seven U.S. Senate incumbents—four Democrats and three Republicans—are retiring from public office, and the 2024 elections saw a slight increase in the average age of newly elected members, rising to 56. The net effect on average age will depend on whether retiring older senators are replaced by younger candidates or similarly-aged successors.